When working in archives I always find it interesting to note what kind of paper used and if ink, pencil or typewriter have been used. Thin paper with typewriter writing fascinates me, because the imprint shows so clearly on the back. The backside thus becomes almost like a piece of art.
I now read quite an old copy of Wilkie Collins' The Woman in White - a book that inspired Dorothy Sayers and which I read about in Reynolds' biography of her. I am not quite sure how books are printed today, but at least the print leaves the pages smooth. In the book I am now reading the the pages have been properly type set, and the imprint has left deep indents. Even though the paper is quite thin, the print does not show through except when there is half a blank page due to a new chapter. This reverse imprint fills me with expectation of what is coming next.